Linear motion guide unit

Abstract

A linear motion guide unit is disclosed in which there is provided a retainer band making it possible to easily fit a roller chain with rollers traveling through a recirculation circuit into a load way of the recirculation circuit, thereby making sure of smooth recirculation of the roller chain. Cooperation of the retainer band with a retainer plate helps guide links of the roller chain in a load way of the recirculation circuit, keeping the roller chain against running out of the load way thereby ensuring smooth movement of the roller chain throughout the recirculation circuit.

1. A linear motion guide unit comprising; an elongated guide rail, a slider arranged on the guide rail for movement relative to the guide rail, a rolling element rolling through a recirculation circuit made in the slider, a rolling-element chain allowed to travel together with the rolling element through the recirculation circuit, and a first retainer band to guide the rolling-element chain along a load area in the recirculation circuit defined between the guide rail and the slider while keeping the rolling-element chain against running out of line; and wherein the first retainer band is installed in the slider in a detachable way allowing the rolling-element chain to fit it into the recirculation circuit from the load area of the recirculation circuit. 
   
   
     2. A linear motion guide unit constructed as defined in  claim 1 , wherein the rolling-element chain is comprised of a retainer including a separator interposed between any two adjoining rolling elements to keep the adjoining rolling elements against rolling contact with one another while keeping the rolling elements against running out of line and a set of parallel resilient links interconnecting in series the adjoining separators with one another, and the rolling element fit in an opening defined by both the adjoining separators and the links interconnecting the separators of the retainer. 
   
   
     3. A linear motion guide unit constructed as defined in  claim 1 , wherein the slider is composed of a carriage having a race to form the load area together with a race of the guide rail between them, and a return passage to return the rolling element from any one of forward and aft ends of the load area back to other end, and end caps secured to forward and aft ends of the carriage, one to each end, and made therein with turnarounds where the rolling-element chain is allowed to turn about in rolling direction, and wherein the recirculation circuit is make up of the load area, return passage and turnaround. 
   
   
     4. A linear motion guide unit constructed as defined in  claim 3 , wherein one of the parallel links of the rolling-element chain fits for traveling in a guide trough that is defined in the load area of the recirculation circuit between the retainer band and a guide shoulder cut in the carriage, while another of the parallel links of the rolling-element chain fits for traveling in another guide trough that is cut in a retainer plate secured to the carriage. 
   
   
     5. A linear motion guide unit constructed as defined in  claim 4 , wherein the retainer plate has a wedge on a surface thereof facing the carriage, a recess on a surface thereof opposite to the wedged surface, and a bore to allow a fastening bolt extend through there after having extended through a bolt hole in the carriage, the wedge being adapted to fit into a V-groove cut in any one side block of the carriage between two rows of the circulation circuits, the recess being adapted to accommodate therein a backup plate with a threaded hole, whereby the retainer plate is secured to the carriage by fitting the wedge into the V-groove, followed by screwing the fastening bolt into the threaded hole in the backup plate. 
   
   
     6. A linear motion guide unit constructed as defined in  claim 4 , wherein the retainer plate has a wedge on a surface thereof facing the carriage, a recess on a surface thereof opposite to the wedged surface, the wedge being adapted to fit into a V-groove cut in any one side block of the carriage between two rows of the circulation circuits, and wherein a fastener band is provided to fit into the recess with lengthwise opposite ends thereof coming into engagement with the forward and aft end caps whereby the retainer plate is secured to the carriage. 
   
   
     7. A linear motion guide unit constructed as defined in  claim 6 , wherein the fastener band is composed of a major part to bear the retainer plate thereon, forward and aft ends bent to make engagement with concaves cut in the end caps, and hooked extremities to fit into depressions cut in sides of the end caps, the concaves in the end cap being made more in depth than the slots that are cut to accommodate the retainer band, which is to keep the one of the parallel links of the rolling-element chain against running out of line. 
   
   
     8. A linear motion guide unit constructed as defined in  claim 3 , wherein the return passage of the recirculation circuit in the carriage is formed within a sleeve installed in a bore in the carriage, the sleeve having a guide slot cut deep to allow the link of the roller chain to move along there. 
   
   
     9. A linear motion guide unit constructed as defined in  claim 1 , wherein the retainer band is made of a metal strip bent to a specific shape, which includes a major retainer part to guide the link to keep it against running out of line, lengthwise opposite ends of the major retainer part bent to make engagement with slots cut in end surfaces of the end caps, and hooked toes at the extremities of the bent ends to come into engagement with dents cut in sides of the end caps. 
   
   
     10. A linear motion guide unit constructed as defined in  claim 9 , wherein the recirculation circuits are arranged on sidewise paired side blocks of the carriage, two rows for each side, the two rows of the recirculation circuits being oriented to intersect each other, and the slots to make engagement with the retainer band are cut in the end surfaces of the end caps in a way that they are different in depth and crossed each other. 
   
   
     11. A linear motion guide unit constructed as defined in  claim 10 , wherein the rolling-element chains are roller chains in which rolling elements are rollers, the roller chains being installed in the two rows of the recirculation circuits, one to each row. 
   
   
     12. A linear motion guide unit constructed as defined in  claim 11 , wherein the retainer plate has lengthwise guide surfaces to guide any axial ends of the rollers in the recirculation circuits, the guide surfaces being made therein with guide troughs for carrying another of the parallel links of the roller chain.